Analysis By Nick Assinder Political correspondent, BBC News website

The row over Derek Conway's use of his parliamentary allowances may have taken some of the heat off Labour as it continues to suffer from its funding crisis.

Mr Conway's case might lead to further claims

But, as the initial furore started to die down, the expression "a can of worms" could be heard echoing throughout Westminster.

And some backbenchers were expressing real fears that there may now be a prolonged and highly-damaging war of attrition as each side attempts to get the dirt on its opponents - something that will do little to rebuild the tarnished reputation of the Commons.

Specifically, many MPs on all sides of the house are worried that this war might lead to a series of allegations about the use of their expenses, secretarial and office allowance - some of which might be genuine, others merely mischievous.

The job is a notorious marriage breaker and anything that helps prevent that must be a good thing Family jobs ban suggested

The situation will not be helped by the fact that there are suspicions some of the rules governing how these allowances are spent are, either accidentally or by design, pretty vague and that too few checks are carried out - for example there is no requirement for MPs to prove how much work employees have carried out.

And the notion amongst some voters that the authorities and other MPs are prepared to turn a blind eye to rule bending or, worse, that they are "all in it together" is already hard enough to dispel.

Outdated rules

There was a possible example during the David Blunkett affair which saw him admitting to using a free parliamentary rail pass for his lover.

The passes are reserved only for "spouses" which, the authorities have confirmed, currently means wife or husband. So unmarried partners are ineligible.

Many MPs employ members of their family

Many believe that is an outdated rule and that partners should be eligible - so might that be a rule which could fall under the "blind eye" heading?

And, if so, how many other such small, but costly regulations might also be seen as outdated, impractical, inequitable or unworkable and, therefore, bendable?

In the specific case of staff allowances, it is perfectly within the rules - and even seen as a good idea in many cases - for MPs to employ members of their family.

The job is a notorious marriage breaker and anything that helps prevent that must be a good thing.

Similarly, it is argued, being an MP is not usually a solo profession - the family is necessarily and often enthusiastically a part of it, so why not bring them into the office?

Audit office

But the fact that some MPs have recently been seen attempting to exempt themselves from freedom of information laws and that there have been ongoing disputes over exactly how transparent they should be over their finances seems to have boosted demands for complete openness.

If the feared war of attrition does indeed now break out, those demands are bound to get louder.

There are already some suggestions of a way forward doing the rounds in Westminster, mostly based around an independent body such as the National Audit Office being given the role of overseeing all MPs' expenses.

But there is another option that has occasionally raised its head in the past - creating a pool of professional office staff appointed and paid by the Parliamentary authorities and allocated to MPs by them.

There might then be a much smaller allowance to each MP to appoint advisers or assistants of their own choosing.

For now, however, it seems likely there will be moves to examine the whole system with a view to more transparency.